Final answer:
Anna most likely contracted the poliovirus from consuming improperly cooked food.
Step-by-step explanation:
Anna was most likely infected with the poliovirus because she consumed food that wasn't cooked to a safe temperature. Poliovirus is transmitted through the fecal-oral route, meaning it spreads through contaminated food or water. If Anna consumed food that was contaminated with the poliovirus and wasn't properly cooked or heated to a safe temperature, she could have become infected.
Learn more about Transmission of poliovirus through contaminated food